Improvement in hot-air furnaces



(w. SANFORD.

Hot Air Furnace.

Patented' May 6, 1862.

N. PETERS. PlwloLnhognphon Walhmgton. D. (L

NITED STATES FATENT OFFICE.

NATSON'SANFORD, OF BROOKLYN, NE\V YORK.

IMPROVEMENT IN HOT-AIR FURNACES.

Specification forming part of Letters Patent No. 35,] 80, dated May 6, 1862.

To aZZ whom it may concern:

Be it known that I, \YATSON SANFORD, of the city of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in. Furnaces or Heaters; and I do hereby delare that the following is a description thereof in terms which I now think sufficiently full, clear, and exact, reference being had to the annexed drawings, making a part of this specification, in which Figure 1 is a top view; Fig. 2, a vertical section in the line :1; r of Fig.1, and Fig. 3 a hori zontal section in the line y y of Fig. 2.

The nature of my invention consists, first, in casting a section of the furnace or heater, or the whole of it, together with sections of smoke-pipe, all in one piece; second, in casting the fire-pot and lower section of the dome in a regular corrugated form, giving channels which serve as smoke-fines; third, in extending the fines down to or alittle below the charge of fuel in the fire-pot, leaving above that point a large and close reverberatory chamber; fourth, in increasing the numberof smoke-fines to that extent and placing them in such position that they shall form regular corrugations around the body of the stove and receive the smoke at or below the surface of the fuel-charge.

To enable others to make and use my invention, I will proceed to describe its con struction and operation.

First. It is an objectof considemble importance to cast the fire-pots of furnaces and heaters in as few pieces as possible, on account of the difficulty experienced in permanently effecting gas -tight joints. Consequently I cast all of that part of my furnace and heaters A above the grate I, when small in size, in one piece, including the first sections of pipe (3 but when the large sizes are to be constructed I consider it only nee :ary to cast in one piece or together that section between the red lines 1 1 and 2 2, or any greater section either above the line 1 1 orbelow the line 2 2, and first sections of stove-pipe C. By these means the smallest possible chance for the escape of the gas from the fire-pot, owing to imperfect joints, is secured and one series of joints dispensed with in the pipe-connections.

Second. Great strength is required in the fire-pots of heaters and furnaces, subject as they are to intense heat and to sudden expansion and contraction, and at the same timeit is desirable to secure a great extent of heatingsurface. I secure these ends by casting the lower part of the upper or dome section, Z), of my furnace or heater into regular corrugations, D, the outer concave portion and the inner convex portion of which are strengthened by an increaseddeposition of metal, 0, and the ribs (1. This form of corrugation yields an extraordinary degree of heating-surface and great strength, and the increased thickness of metal at c and the ribs (Z add greatly to this strength, and ata point, too,where there is the most need of it-viz., at that point where the incandescent fuel comes in direct contact with the fire-pot. The ribs (I serve another purpose. They are continuations of the ribs c in the lower section, E, of the fire-pot, as the corrugations D are continuations of the corrugations f in the same section. \Vhen, therefore, these lower corrugations, and sometimes parts of the upper, are filled with fire-clay or like material, as is designed to be done at the option of the manufacturer, these ribs keep the coal away from the fire-clay, and thus prevent the adhesion thereto of clinkers,which are formed in the combustion of stone or anthracite coal. The corrugations D, it will be observed, continue upwardly and take the form of the first section of stove pipe or collarC. By this construction the inflammable gases and heated smoke are forced within the concave portions of the corrugations I) and heat the whole surface thereof equally throughout.

Third. Another important consideration is to accumulate and confine the gases until they are highly heated, and then to pass them oif at a point where they shall be sure of ignition and thorough combustion. I effect this by providing a large overhanging dome, I), called a reverberatory chamber, into which all the gases rise as they are formed and become heated to a high temperature, and by extendin g the smoke-fiues or corrugations D down to or a little below the surface of the f uel-charge, the surface of which is a little below the red line 1 By this arrangement it is foundby experiment that all the inflammable gases are burned and a saving of at least one-third the fuel effected. This is because the gases are first collected and heated to the point of ignition, and then drawn down upon the glowing fuel-charge, where a thorough combustion takes place.

Fourth. Another point of great importance in connection with the third is to diffuse the heat equably all around the fire-p0t, so as to turn to account its entire surface. I do this by distributing the smoke-pipes or corrugations D around the fire-pot at short and equal distances apart, so that no part of the fire-pot (except the mouth or coal-hole, which may be placed in the dome, if desired, and pipes or corrugations substituted on the side of the fire-pot) is not equally affected by the heat. The weight attachable to this improvement, in conjunction with the overhanging dome, and the feature of extending the smokefiues down to or below the fuel-charge, may be estimated when it is observed that in fire-pots with one or even more smoke-flues,when such flues are not of themselves the entire surface of the fire-pot, as mine are, those parts near the smoke-flue become redhot,while the other parts remain thus unaffected unless the degree of heat becomes alike all around by convection. By my arrangement no part of the fire-pot at any time is liable to be unequally heated, and this fact is of prime importance when it is considered how liable fire-pots are to break by reason of unequal expansion and contraction due to unequal heat.

If thought necessary or proper, I cast my dome with an opening in its apex at the point represented by the red line z z, to receive a cover or a smoke-pipe to effect a direct draft.

Having thus described my invention and pointed out the manner in which it operates, what I claim therein, and desire to secure by Letters Patent of the United States, is

1. Casting the fire-pot and dome, or the section between the red lines 1 1 and 2 2, or any greater section either above the line 1 l or below the line 2 2, together with the first section of smoke fines or pipes, all in one piece, substantially as and for the purposes described.

2. Forming the fire-pot as well as the lower section of the dome with corrugations which shall be continuations of each other, the interior concave parts of which form the exits for the smoke or thecommencement of the smoke-fines, as and for the purposes set forth.

3. Providing the furnace or heater with an enlarged dome, b, in combination with the extension of the corrugations or smoke-Hues D, by means of the corrugations f, or their equivalents, down to or below the surface of the fuel-charge, substantially as above set forth.

4. In combination with the enlarged dome and corrugations or smoke-fines so located that is, extending down to or below the 'surface of the fuel-chargethe distribution of the smoke-exits all around the body of the fire-pot and near together, so as to make regular corrugations, for the purposes and substantially as indicated.

WATSON SANFORD. WVitn ess es JOHN R. KENNADAY, O. F. SHAW. 

